Electronic watches are accurate, reliable and offer a wide variety of features and options. Such watches typically contain a printed circuit board, a display and a battery housed within a watch casing. The printed circuit board carries the electronic circuitry necessary to control the display and the various functions of the watch. In addition, the printed circuit board includes connections for mechanical, push-button switches that allow a wearer to control the functions of the watch.
For years, the shape of a watch casing has been dictated largely by the printed circuit board, its related components, and the push-button switches. Moreover, because of the expense involved in designing and manufacturing printed circuit boards, a few standard circuit board designs were used by most watch manufacturers to manufacture most watches. For each of the standard circuit boards, the push-button switches had to be located to physically engage the printed circuit board at the proper location. As a result, flexibility in the placement of the push-button switches has been very limited.
Then, it was recognized that the switches could be hardwired to the printed circuit board. Hardwiring allowed the push-button switches to be placed anywhere on the casing and still be coupled to the circuit board with a wire connection. This type of design permitted much more latitude in casing designs.
However, the design of varied and unique casings brought with it its own problems. If the casings were hollow shells into which the printed circuit boards fit, each casing required unique spacers and bracketry to hold the printed circuit board and other watch components in place.
If, on the other hand, the casings were made from resins molded around the printed circuit boards, such as in Kume et al., U.S. Pat. No. 4,194,351, then molds for forming the casing were required. If a flaw or blemish occurred in the casing as the resin set, the casing and the enclosed printed circuit board would be ruined and likely discarded. Moreover, the resin forming the casing must generally be heated to a relatively high temperature to achieve the necessary casing strength. This heating could damage the heat-susceptible printed circuit board inside. Also, the design of the casing was somewhat limited because the casing had to be shaped to allow removal of the mold.
Thus, a need exists for a watch and a method of assembling a watch that overcomes these inadequacies.